Fsd Lane Change Balking - Faulty Sensor?

[johnny2678]

Hi all, first post. I've had my M3 AWD LR w/ FSD (that's a mouthful) for about 2 months. I regularly make drives of 200-300 miles. Curious about the phenomenon that happens in the video below when FSD decides to changes lanes. Looks like the car thinks something is off my left front bumper so it won't change lanes.

To make it worse, sometimes it starts the lane change and then swerves back when the sensor is tripped before the changes completes forcing me to override FSD. Of course there's nothing there to swerve from. The people behind me must think I'm nuts.

Any thoughts, comments? Faulty prox sensor?

ps. Just remembered, I might have manually requested the lane change in this video so I could record it happening, but it happens during manual FSD lane changes and automatic FSD lane changes

 

[ewoodrick]

It's basically the car deciding that something just ain't perfect for lane changing, it happens to everyone.
It could be that car isn't seeing the lines that well, or a false detection.

The car is deciding that it's better safe than sorry.

 

[johnny2678]

It's basically the car deciding that something just ain't perfect for lane changing, it happens to everyone.
It could be that car isn't seeing the lines that well, or a false detection.

The car is deciding that it's better safe than sorry.

yea, I had that thought too. But then I wondered why it only happens when I'm getting into a lane to my left - happens about 50-75% of the time when changing to a lane on the left. Never happens when the car is moving back over to the right. And usually only happens on a 3 lane highway.

 

[StellarRat]

I think you'll find this is improved in a later update.

 

[johnny2678]

Good to hear @StellarRat !

Inside info?...

 

[StellarRat]

Good to hear @StellarRat !

Inside info?...

No, but I have 2019.20.2.5 and it seems much less hesitant about changing lanes. At least that's what I think compared to earlier versions. You'll have to make up your own mind about that one. It still requires a good sized "hole" before it's willing to try though. Much more than a human would probably consider necessary. I haven't tried it in heavy traffic, but my feeling is that it still won't work under those conditions.

 

[johnny2678]

No, but I have 2019.20.2.5 and it seems much less hesitant about changing lanes. At least that's what I think compared to earlier versions. You'll have to make up your own mind about that one.

Looking forward to it! Unfortunately, car is now in the shop after getting rear-ended 2 days ago. By the time I get it back, who knows what version we'll be on

 

[SeanM]

Looking forward to it! Unfortunately, car is now in the shop after getting rear-ended 2 days ago. By the time I get it back, who knows what version we'll be on

Wow!! Sorry to hear about the accident. Better inform your issue to their tech team, so they can check if any sensors are faulty.
All the best.

 

[Peteski]

Pretty normal behaviour in my 2018 MX. I was wondering if M3 was more robust with latest hardware, but seems not! For me auto lane-change has always been a bit dubious. It's a while since I've had the full aborted swerve back mid lane change, but it often refuses to activate for no good reason.

 

[johnny2678]

Pretty normal behaviour in my 2018 MX. I was wondering if M3 was more robust with latest hardware, but seems not! For me auto lane-change has always been a bit dubious. It's a while since I've had the full aborted swerve back mid lane change, but it often refuses to activate for no good reason.

yea, it's usually spot on determining when a lane change needs to happen - it's just hesitating to see it through because the sensor thinks something is there for some reason. Good to hear that's the expereince of others as well. Gives me hope the software will get better and it's not just me, or my car.

Wow!! Sorry to hear about the accident. Better inform your issue to their tech team, so they can check if any sensors are faulty.
All the best.

Thanks! Authorized Body Shop told me once they plug the laptop in, Tesla just starts singing to them about which sensors are faulty/broken/off. So hopefully they would catch it if it's a bad sensor. I will bring it to their attention, just in case.

 

[tonman]

I've experienced your second issue. On a 300 mile road trip it was really bad and thought that same as you, the drivers around me must think I'm sauced. The swerve back to the lane is so dramatic. I will say it was really bad on that trip and didn't really happen much after, not sure if software update helped, or just a reset.

 

[johnny2678]

It's because the lane to your left is orange, it does the same with me... Full self driving thinks it's probably a carpool lane. Don't know where your from but I'm from los angeles and the only lane that has orange is the carpool and you can't cross it unless it breaks ( otherwise it's a 400+ ticket)

Maybe? But the car wants to change lanes (either via auto lane change or a manual push of the turn signal), orange or not. It's the sensors that are keeping it from doing so. At least thats' what I think is happening.

 

[JTesmod3]

Maybe? But the car wants to change lanes (either via auto lane change or a manual push of the turn signal), orange or not. It's the sensors that are keeping it from doing so. At least thats' what I think is happening.

I actually looked at your video again and noticed that the car was sensing something close to you on the left side....i deleted my post as soon as i rewatched it; your fast!

I'll try it while I'm in the roads with the orange Lanes and get back to you

 

[johnny2678]

I actually looked at your video again and noticed that the car was sensing something close to you on the left side....i deleted my post as soon as i rewatched it; your fast!

haha, no worries! I'm a VIMEO noob and it doesn't look like there is a way to blow up the video or open it in a new tab when you use the standard video tags.

Plus with the FL glare on the screen it's easy to miss the sensor indicator going off.

 

[johnny2678]

Just to be completely pedantic, this is Autopilot, not FSD.

yea sorry, I'm not very clear on the demarc line for AP vs FSD - thought lane change was the latter. Plus the car is confusing. When you put in an address, doesn't it say 'Navigate on Autopilot' - but it's actually FSD?

 

[JTesmod3]

Im on a road trip to san Francisco right now with an identical road; its having no problems switching lanes

 

[aymelis]

Hi all, first post. I've had my M3 AWD LR w/ FSD (that's a mouthful) for about 2 months. I regularly make drives of 200-300 miles. Curious about the phenomenon that happens in the video below when FSD decides to changes lanes. Looks like the car thinks something is off my left front bumper so it won't change lanes.

To make it worse, sometimes it starts the lane change and then swerves back when the sensor is tripped before the changes completes forcing me to override FSD. Of course there's nothing there to swerve from. The people behind me must think I'm nuts.

Any thoughts, comments? Faulty prox sensor?

ps. Just remembered, I might have manually requested the lane change in this video so I could record it happening, but it happens during manual FSD lane changes and automatic FSD lane changes

Same issue here after i got a hitch installed: had to remove the rear bumper, hence disconnect the sensors. For me it's the right lane that the car is avoiding, changing lane to the left works just fine. Not a software problem. Was working perfectly before hitch installed, same software.

 

[aymelis]

Same issue here after i got a hitch installed: had to remove the rear bumper, hence disconnect the sensors. For me it's the right lane that the car is avoiding, changing lane to the left works just fine. Not a software problem. Was working perfectly before hitch installed, same software.

As a follow up, was nothing to do with the sensors. It ended up in my case being the rear right blinker not reconnected. Autopilot was canceling lane change because the blinker was not working, but there was no specific message.

 

[Mrcarcrazy]

yea, I had that thought too. But then I wondered why it only happens when I'm getting into a lane to my left - happens about 50-75% of the time when changing to a lane on the left. Never happens when the car is moving back over to the right. And usually only happens on a 3 lane highway.

I have exact same experience. Only to the left!

I’ve determined it’s just the way it is.